I've been trying to do some reading up on the use of flaked oats and mashing, but I can't seem to find too many specifics.

I'm wondering if the use of flaked oats (like around 1 lb per 5 gal) in the mash will it affect your efficiency while sparging out? It seems like the oats might make the mash "thicker" and more difficult to sparge out. Any thoughts would be appreciated.

Okay, good to get confirmation of that possibility. I recently used oats in a recipe and my efficiency came out lower than expected and I've been trying to put a finger on the reason. My system isn't the most efficient to begin with, so I think the oats just compounded the problem. Thankfully, I had compensated for my average lower efficiency and so my gravity was still within the target range for the style. Big thanks!

highwaytoale wrote:I recently used oats in a recipe and my efficiency came out lower than expected and I've been trying to put a finger on the reason. My system isn't the most efficient to begin with, so I think the oats just compounded the problem.

Are you taking into account that Oats has a lower potential sugar contribution than Barley? Oats has an extract potential of about 31 ppg instead of the 36 ppg you might expect from standard malted 2-row barley, so you could have the same efficiency but get a lower OG from a recipe that contains Oats.

Do you know if your low efficiency is due to low Conversion Efficiency or low Lauter Efficiency? Check the gravity of your mash liquor against your mash thickness using this chart and wait until your conversion is well into the 90% range before taking your first runnings. A coarse crush, low mash temperatures, thick mashes, and a number of factors that affect starch gelatinization can result in needing a mash longer than the, often quoted, 60 minutes.

If you're typical low efficiency is due to less than 100% conversion, then Oats could lower this further because they have no amylase enzyme and the starches may be somewhat less available.

I did use the lower ppg for the oats in my calculations so I don't think it was that.

I hadn't thought about conversion efficiency, but I do always do the standard iodine conversion test. If I pass the iodine test does that mean that my conversion is good or could it still be off and the gravity must be measured?

If I had to bet on it, I'd guess that it's mainly my lautering efficiency that's driving it. I use the typical, rectangular cooler mash-tun with only a single copper pipe manifold. I think I should consider adding a second pipe.

highwaytoale wrote:If I pass the iodine test does that mean that my conversion is good or could it still be off and the gravity must be measured?

I'm not sure, but it's probably worth checking.

If I had to bet on it, I'd guess that it's mainly my lautering efficiency that's driving it. I use the typical, rectangular cooler mash-tun with only a single copper pipe manifold. I think I should consider adding a second pipe.

If you batch sparge, it shouldn't matter as long as the tun drains as completely as possible, but if you fly sparge it may be insufficient. I think John Palmer's experiments showed that you want pipes set about 2 inches apart.